The Design of Everyday Things

Chapter 1 argues that good design must be human-centered. Placing humans at the forefront of design requires understanding how people interact with machines. Norman introduces key concepts that underlie good design: discoverability (what actions are possible) and understanding (how products should be used). Doors without handles and hinges, for example, lack discoverability and hinder understanding. Norman argues that simple inventions should not require user manuals and that overly-complicated products epitomize failed design. This opening sets the tone for the rest of the book, which builds out from this premise—design should be intuitive and easy to use.

The Complexity of Modern Devices

Design is a relatively new field that encompasses all artificial things, from clothing, to furniture, to bridges. Norman writes about everyday things, focusing on the interplay between users and technology. His approach was unique in the 1980s because it combined three major design areas normally considered distinct: 1) industrial design, or the creation and development of products and systems that optimize function, appearance, and value for users and manufacturers; 2) interaction design, an area that draws on psychology, art, and emotion to understand how humans interact with technology; and 3) experience design, which focuses on user enjoyment.

Norman argues that failures and accidents generally result from bad design, not user error. Technological limitations, efforts to keep costs down, and a lack of understanding of design principles produce deficiencies in human-machine interactions. To improve products, engineers must strive to understand people rather than focus on logic. This novel approach to design established Norman as a leader in his field, while the longevity of his ideas attests to their strength and continued relevance.

Human-Centered Design

Norman presents human-centered design (HCD) as a solution to design challenges. HCD is a design philosophy that places user needs, capabilities, and behaviors at the forefront of the design process. Norman argues that good design requires understanding technology and psychology, as well as good communication between machines and people. Observation, testing, and adaptation are key to understanding people’s needs.

Norman’s human-centered approach to design has been widely adopted, which speaks to its efficacy in a variety of fields. For example, The Handbook of Human-Machine Interaction: A Human-Centered Design Approach (2011) contains essays by twenty designers, psychologists, and engineers exploring various facets of human-machine interactions, with an emphasis on computerized devices. More recently, researchers have applied Norman’s idea of HCD to the development of artificial intelligence. In a 2020 article for Synergy entitled “Human-Centered AI: The Role of Human-Centered Design Research in the Development of AI,” Jan Auernhammer urged researchers to design AI systems for people using a human-centered approach.

Fundamental Principles of Interaction

Norman describes five concepts that facilitate human and product interaction, all drawn from the field of cognitive psychology. Norman defines the fundamental principles of interaction as follows:

1) Affordances describe the relationship between physical objects and people. For example, glass affords transparency and, therefore, affords seeing through, but it does not afford the passage of air or physical objects (aside from atomic particles). Some affordances are perceivable, while others are not. Norman focuses on what technologies afford, in contrast to later scholars, who expand the term to include how, for whom, and under what circumstances technologies afford.

2) Signifiers communicate how something should be used. In contrast to affordances, which determine what actions are possible, signifiers communicate where actions should take place. Signifiers must be perceivable, like a PUSH sign on a door.

3) Constraints guide user actions by establishing limits or parameters.

4) Mapping is a mathematical term referring to the relationship between the components of two sets of things. The concept is particularly important in the design of controls. For example, when users confront a row of light switches, mapping will indicate which switch corresponds to which light. According to Norman, the best mappings are intuitive, with controls being close to the thing being controlled.

5) Feedback communicates the results of an action. Feedback must be immediate and informative to be effective. A red flashing light is poor feedback because it does not tell users what is wrong or how to solve the problem. Poor feedback, as well as too much feedback, can be worse than receiving no feedback. Effective feedback is planned, unobtrusive, and prioritized.

Norman’s five principles of interaction operate alongside a sixth concept, which he calls the conceptual model. Conceptual models are simplified, and sometimes inaccurate, explanations of how things work. For example, folder icons refer to documents, even though no folders exist inside computers. Good conceptual models allow users to predict the effects of their actions.

The System Image

The term “system image” refers to the combined information available to users about products. This includes what a product looks like, what users know of similar products, and information from pamphlets, advertisements, articles, instruction manuals, and salespeople. An incomplete or contradictory system image hinders use of the product. It is the designer’s job to provide appropriate information to make products understandable and usable.

The Paradox of Technology

Technology can simplify life and make it more enjoyable. However, increasingly complex technologies can make products hard to use and lead to user frustration. Norman discusses smartwatches to make this point. Smartwatches serve dozens of functions beyond telling the time, but their small screens make them difficult to use.

The Design Challenge

Norman argues that good design requires interdisciplinary cooperation. Product managers lead large teams whose members have competing priorities. For instance, one discipline might emphasize usability, while another might stress aesthetics. Product managers must also take price, reliability, and marketability into account. Although good design is challenging, it is achievable through an interdisciplinary approach: “If the design team has representatives from all the constituencies present at the same time, it is often possible to reach satisfactory solutions for all the needs” (35). It is therefore important to have cross-disciplinary communication and cooperation to ensure that the needs of all groups are being met in designing a product.